You can see a map of these nodes with https://wigle.net/
While LG TVs send a lot of private data when connected to the internet, I'm not aware of any credible reports that they automatically connect to open or partner-provided wifi networks without a user choosing to do so.
It's certainly a threat to keep an eye open for, but it seems manufacturers haven't quite stooped to that low yet.
It has not been demonstrated actively in use, only that it is possible and trivial to implement. Statement with regards to it being demonstrated retracted.
I stand by the concept that any consumer IoT device could join these networks, and the end user would never know. The only legal solution to this problem statement is to physically disable the radio on the device if assurance is desired.
This depends a lot on the region/country. IN the US, open WiFi is unusual but it's pretty common in parts of asia, for example.